Portuguese Man o' War sting more than 50 people on Mumbai beaches.

More than fifty people, including several children, have been stung by Portuguese Man o' War, Physalia physalis, on beaches around the city of Mumbai in Maharashtra State, India, this week, with a number requiring hospital treatment as a consequence. Many city residents have been visiting the beaches in the past few days, as Monsoon rains have begun to ease up in the area, but this has brought them into contact with the venomous Cnidarians, which have proliferated off the coast in the recent hot weather.

A Portuguese Man o' War, Physalia physalis. Islands in the Sea 2002/NOAA/Wikimedia Commons.

Portuguese Man o' War are colonial Siphonophores only distantly related to true Jellyfish, Scyphozoa, though commonly referred to as such. Their bodies are made up of thousands of individual zooids, each with their own sting, tentacles and digestive system. New zooids are formed by budding from other members of the colony, but remain attached to these to form a single colony. Each year a generation of specialist sexual zooids (gonozoids) is produced which produce eggs and sperm, with fertilised eggs going on to form new colonies. These animals are anchored to the sea surface by a highly modified zooid which forms an air sack, filled with a mixture of carbon monoxide defused from the zooid and nitrogen, oxygen and argon from the atmosphere, which are brought into the sack through osmosis. Portuguese Man o' War produce an extremely strong venom, for both capturing food and defending the colony, and which is capable of causing extremely painful stings, and sometimes death, in Humans, for which reason people are advised to be extremely cautious on beaches where these animals wash up, not just of entire animals but also detached tentacles, which are less visible but still capable of stinging.

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Lepidochelys olivacea: Olive Ridley Turtles colonise Mumbai beach.

Around eighty hatchling Olive Ridley Turtles, Lepidochelys olivacea, were observed crawling down Versova Beach in Mumbai on Thursday 22 March 2018, prompting a search by volunteers who found a nest site on Friday 23 March. The coast of Maharashtra State, India, is thought to provide nesting sites for about 600 Olive Ridleys, but they are not usually found on Mumbai's heavily polluted beaches. However Versova Beach has been the subject of a cleanup campaign by a the Versova Residents Volunteers, a community-led environmental group which has removed about 13 million kg of plastic and other materials since 2015. The last report of a Turtle nest in Mumbai was over 20 years ago, though this was not photographed or observed by scientists and is generally regarded as apocryphal. An injured Olive Ridley was found on Juhu Beach in Mumbai, and treated by a local vet, but it is not thought that this Turtle was nesting.

Hatchling Olive Ridley Turtles on Versova Beach, Mumbai, on 22 March 2018. Afroz Shah/Versova Residents Volunteers.

Olive Ridleys are the smallest, and most abundant, species of Sea Turtles, though they are still considered to be Vulnerable under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species, due to the threat posed to their breeding grounds by Human activity, and the (now illegal) trade in meat, eggs and leather from these Turtles. The species is slow to colonise new nesting areas, as females usually return to the beaches where they were born to lay eggs. In India the species has been the subject of a deliberate re-introduction scheme in Orissa Stste, but the colonisation of a beach in Mumbai is both unexpected and welcomed by environmentalists.

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Seven dead in Maharashtra flooding and related events.

Seven people are known to have died in flooding and other rain-related  events in Maharashtra State, India on Tuesday 29 August 2017. Two people drowned in separate incidents in the city of Thane; one of whom has been identified as Gauri Jailwa, 14, and the second only as a 32-year-old-woman. In Mumbai, Kalyani Jangam, 2, died in a building collapse in the suburb of Vikhroli, and Nikhil Pal, 2, and Suresh Mourya, 40, died in a similar incident in the Panchasheel Chawl. Two more, as yet unnamed people are said to have died in a landslide in Vikhroli. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall.

 Flooding in Mumbai this week. Times of India.

The Mumbai area has been suffering its worst flooding since 2005, part of an exceptionally severe monsoon which has affected much of India this year. The floods have caused severe disruption to the city's transport network and other facilities, with airports closed due to the rains, many rail services suspended due to a series of landslides affecting train lines to and from the city, and many roads either flooded or blocked by abandoned cars. The majority of the city's schools have now closed, along with many other facilities and businesses, and there are concerns about the availability of drinking water in many parts of the city, and floodwaters are generally heavily tainted with rubbish.

Flooding in Mumbai on 29 August 2017. Punit Paranjpe/AFP/Getty Images.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate. This situation is particularly intense in South Asia, due to the presence of the Himalayas. High mountain ranges tend to force winds hitting them upwards, which amplifies the South Asian Summer Monsoon, with higher winds leading to more upward air movement, thus drawing in further air from the sea. 

Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

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Flooding after Mumbai hit by freak waves.

Parts of the Indian city of Mumbai are suffering from flooding after being hit by a series of freak waves on Thursday 12 June 2014. The waves occurred around high tide, and rose over four meters above expected levels, inundating low lying coastal parts of the city and causing damage to homes and vehicles, as well as dumping considerable amounts of rubbish and marine sediments on the streets of the city.

Flooding in Mumbai on Thursday 12 June 2014. IBN Live.

The India Meteorological Department has attributed the waves to strong onshore winds associated with Tropical Storm Nanauk which coincided with a high spring tide, and warn that there is a danger of similar events for the next week. The Arabian Sea coast of India is currently waiting for the start of the year's monsoon season, a time when it is particularly vulnerable to wind-driven flooding.

Areas of Mumbai affected by coastal flooding on 12 June 2014. Google Maps.

Tropical storms are caused by the warming effect of the Sun over tropical seas. As the air warms it expands, causing a drop in air pressure, and rises, causing air from outside the area to rush in to replace it. If this happens over a sufficiently wide area then the inrushing winds will be affected by centrifugal forces caused by the Earth's rotation (the Coriolis effect). This means that winds will be deflected clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere, eventually creating a large, rotating Tropical Storm.

Tropical Storm Nanauk has been moving northwards in the central Arabian Sea for several days, and has proved hard to track. After initial fears that it would hit Oman and the Gulf States, it is now thought likely that it will peter out without making landfall.

The path of Tropical Storm Nanauk to date (thick line) and its predicted future movement (thin line, circles represent the margin of error on the predictions). Colours represent the strength of the storm. Tropical Storm Risk.

Satellite track of the movements of Tropical Storm Nanauk on the morning of Friday 14 June 2014. Cyclocane.

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 13 killed by lightning in West Bengal.

At least thirteen people have been killed by lightning in West Bengal during the last week, and over twenty more have been injured as the annual kalboishakhi storms swept across the state. Most of those...

 Cyclone Helen kills 10 in Andhra Pradesh.

Ten people are known to have died and several more are missing after Cyclone Helen made landfall in Andhra Pradesh State, India, at about 1.30 pm local time (8.00 am GMT) on Friday 22 November...

 Cyclone Phailin kills 23 people in Orissa and Andhra Pradesh.

Twenty three people are now known to have died after Cyclone Phailin made landfall in Orissa State, India, slightly after 9.00 pm local time on Saturday 12 October 2013, brining with it winds of...

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Five dead after landslide at Antop Hill, Mumbai.

Five people have died following a landslide in the Antop Hill area of central Mumbai on Wednesday 10 July 2013. The incident happened at around 7.40 am local time (around 2.10 am GMT), when a large boulder came free near the top of a 20 m slope, tumbling down and striking a series of homes in the process. The five dead have been named as 44-year-old Ramavatar Kevat and his son Sandeep (23), described as an electrician who had been working away for several days, and 25-year-old Sultana Shaikh and her children Arif and Rizwan, both under two years old. Sultana's husband, Salim Shaikh, is being treated in Sion Hospital with a fractured leg. The Shaikh family are said to have moved to Mumbai from Ratnagiri in the south of Maharashtra State 15 days previous to the event.

Rescuers searching for survivors at the scene of the Antop Hill landslide on Wednesday 10 July 2013. Vivek Bendre/The Hindu.

The landslide occurred at a site called Devram Dada Chawl (the term 'chawl' usually refers to a tenement building containing numerous single-room apartments, but in this instance appears to indicate a number of small houses, rented from the owner of the site), which has been struck be several such incidents in the last few years. The Municipal Corporation of Greater Mumbai has recommended that people vacate the site during the Monsoon Season, but has declined to offer alternative accommodation as they are private tenants.

The approximate location of the 10 July 2013 Antop Hill landslide. Google Maps.

The event took place after a night of heavy rainfall, with 35 mm of rain falling in the hour before the landslide. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall.

See also Six people killed by landslide in Nainital District, Uttarakhand, Seven killed by landslide in Uttarakhand, Two teenage girls killed by landslide in Jammu and Kashmir, Woman killed in landslide in Jammu and Kashmir and Man killed in Kerala Landslide.

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